<div class="btn-group btn-group-toggle">
  <label class="btn-primary" ngbButtonLabel>
    <input type="checkbox" ngbButton [(ngModel)]="model.left"> Left (pre-checked)
  </label>
  <label class="btn-primary" ngbButtonLabel>
    <input type="checkbox" ngbButton [(ngModel)]="model.middle"> Middle
  </label>
  <label class="btn-primary" ngbButtonLabel>
    <input type="checkbox" ngbButton [(ngModel)]="model.right"> Right
  </label>
</div>
<hr>
<pre>{{model | json}}</pre>
